5.2.4.1 Translation limits

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273 The implementation shall be able to translate and execute at least one program that contains at least one instance of every one of the following limits:¹³⁾

274 — 127 nesting levels of blocks

275 — 63 nesting levels of conditional inclusion

276 — 12 pointer, array, and function declarators (in any combinations) modifying an arithmetic, structure, union, or incomplete type in a declaration

277 — 63 nesting levels of parenthesized declarators within a full declarator

278 — 63 nesting levels of parenthesized expressions within a full expression

279 — 63 significant initial characters in an internal identifier or a macro name (each universal character name or extended source character is considered a single character)

280 — 31 significant initial characters in an external identifier (each universal character name specifying a short identifier of 0000FFFF or less is considered 6 characters, each universal character name specifying a short identifier of 00010000 or more is considered 10 characters, and each extended source character is considered the same number of characters as the corresponding universal character name, if any)¹⁴⁾

281 13) Implementations should avoid imposing fixed translation limits whenever possible.

282 — 4095 external identifiers in one translation unit

283 — 511 identifiers with block scope declared in one block

284 — 4095 macro identifiers simultaneously defined in one preprocessing translation unit

285 — 127 parameters in one function definition

286 — 127 arguments in one function call

287 — 127 parameters in one macro definition

288 — 127 arguments in one macro invocation

289 — 4095 characters in a logical source line

290 — 4095 characters in a character string literal or wide string literal (after concatenation)

291 — 65535 bytes in an object (in a hosted environment only)

292 — 15 nesting levels for #included files

293 — 1023 case labels for a switch statement (excluding those for any nested switch statements)

294 — 1023 members in a single structure or union

295 — 1023 enumeration constants in a single enumeration

296 — 63 levels of nested structure or union definitions in a single struct-declaration-list